Guide wires and other tools used for assisting insertion of medical devices such as catheters into the body are inserted into and optionally placed in blood vessels, respiratory tracts, urethra, and other body cavities or tissues. When a medical device such as a catheter or guide wire is inserted into the body, the medical device may damage the tissue or the like in the body and produce inflammation or cause pain to the patient. To ameliorate these problems, it has been desired to improve the sliding properties of the medical devices intended to be inserted into the body.
Moreover, the insertion of a syringe needle into the body may also damage the tissue or the like in the body and cause pain to the patient. Furthermore, if the inner surface of a syringe needle, a metal tube in a medical device or equipment, or other metal devices exhibits reduced lubricity when wetted, there may be difficulties in rapidly and accurately delivering chemicals or blood. Accordingly, it has also been desired to improve and maintain the lubricity of the inner surface of these devices when wetted.
Various methods have therefore been tried to solve the above problems, including, for example, methods of coating the surface of a medical device with a hydrophilic resin, a fluororesin, or the like to impart lubricity. However, these methods have the problem that the coating resin is easily peeled or removed from the surface, resulting in deterioration in the sliding properties of the medical device. Accordingly, there is a need for the development of metal medical devices that exhibit reduced deterioration in sliding properties, or syringe needles, metal tubes in medical devices or equipment, or other metal devices that exhibit reduced deterioration in the lubricity of the inner surface when wetted.